local gfx <const> = playdate.graphics

local ButtonFont <const> = FontFullCircle

--- Assumes that background image is of size:
---
--- XXX
--- XOX
---
--- Where each character is the size of the screen, and 'O' is the default view.
function getDrawOffset(ballX, ballY)
    local offsetX, offsetY
    if ballY > C.Screen.H or ballX >= C.BallOffscreen then
        return 0, 0
    end
    -- Keep the ball approximately in the center, once it's past C.Center.y - 30
    offsetY = math.max(0, (-1 * ballY) + C.Center.y - 30)

    if ballX >= 0 and ballX <= C.Screen.W then
        offsetX = 0
    elseif ballX < 0 then
        offsetX = math.max(-1 * C.Screen.W, ballX * -1)
    elseif ballX > C.Screen.W then
        offsetX = math.min(C.Screen.W * 2, (ballX * -1) + C.Screen.W)
    end

    return offsetX * 1.3, offsetY
end

local buttonBlinker = gfx.animation.blinker.new(750, 500, true)
buttonBlinker:start()

--- Requires calling `playdate.graphics.animation.blinker.updateAll()` during `update()` to blink correctly.
function drawButton(buttonLabel, x, y)
    gfx.setColor(gfx.kColorWhite)
    gfx.fillCircleAtPoint(x + 4, y + 7, 12)
    gfx.setColor(gfx.kColorBlack)
    if buttonBlinker.on then
        gfx.setLineWidth(1)
        gfx.drawCircleAtPoint(x + 4, y + 7, 10)
    end
    ButtonFont:drawText(buttonLabel, x, y)
end

---@class Blipper
---@field draw fun(self: self, disableBlipping: boolean, x: number, y: number)
blipper = {}

--- Build an object that simply "blips" between the given images at the given interval.
--- Expects `playdate.graphics.animation.blinker.updateAll()` to be called on every update.
function blipper.new(msInterval, spriteCollection)
    local blinker = gfx.animation.blinker.new(msInterval, msInterval, true)
    blinker:start()
    return {
        blinker = blinker,
        draw = function(self, disableBlipping, x, y, hasSpriteIndex)
            local spriteBundle = spriteCollection[hasSpriteIndex.spriteIndex]
            local currentImage = (disableBlipping or self.blinker.on) and spriteBundle.lowHat or spriteBundle.smiling
            local offsetY = currentImage == spriteBundle.lowHat and -1 or 0
            currentImage:draw(x, y + offsetY)
        end,
    }
end